Project Summary/Abstract HIV incidence among people who inject drugs (PWID) in New York City (NYC) has reached its lowest rate in the past two decades. This achievement is linked to increased access to sterile syringes, drug treatment, and HIV antiretroviral therapy. Despite significant reductions in HIV prevalence among NYC PWID (from 50% in the 1980s to 12% today), injection-related transmission persists. Migrant PWID in NYC who began injecting in Puerto Rico (P.R.) are a key component of the PWID population that contributes to ongoing HIV incidence in the U.S. Migrant Puerto Rican PWID in NYC have pronounced language barriers, very high HCV prevalence, and significantly higher injection risk behaviors when compared to U.S.-born PWID (including U.S.-born Puerto Ricans). As a result, HIV and HCV prevalence is high in this population. In NYC in 2012, Hispanics were 45% of new HIV cases among PWID, and 39% of these new HIV cases among Hispanics occurred among migrant Puerto Ricans. Studies also suggest HIV infection in NYC is a likely outcome for many migrants. Currently, P.R.'s economic crisis is fueling the migration of thousands of Puerto Ricans to the U.S. mainland. Many of these are PWID searching for access to services that are scarce in P.R.: Drug and HIV/HCV treatment. Still, too many continue to engage in injection risks regardless of access to these services. While the presence of ?native? norms influencing their injection risks are documented (e.g., a ?Puerto Rican-way? to inject drugs endorsing syringe sharing among ?brothers?), the extent of these risk norms, and their persistence over time, remain elusive. Because we do not understand these phenomena, we remain unprepared to help this population avoid acquiring and/or transmitting HIV/HCV after migration. We hypothesize there are two norm- related mechanisms influencing injection risks: (1) risk-acculturation ? a process where through migrants' engagement in prevention programs they adopt NYC-specific [less risky] injection norms while replacing native [riskier] ones; and (2) risk-enculturation ? whereby migrants may retain elements of their native injection norms despite access to services. Our goal is to help reduce health disparities by developing a risk-acculturation intervention to curb HIV/HCV infections in this population. To do this, we will conduct an exploratory study with 65 migrant Puerto Rican PWID, and 6 of their service providers, that will: 1) identify the native risk norms -and other influences- that require risk-acculturation, 2) explore existing risk reduction programs and services to identify limitations, and 3) develop and pilot test components of a risk-acculturation intervention for migrants. We will use a multilayered qualitative approach: 1) in-depth longitudinal interviews with 40 migrants, 2) two institutional ethnographies (one-time in-depth interviews with 10 migrants, and 6 service providers; coupled with structured observations), and 3) three focus groups (N=15 migrants). Intervention Mapping protocols will guide the intervention development process. Results will serve as a blueprint in the development of a comprehensive risk-acculturation intervention for migrant Puerto Rican PWID in a subsequent R34 proposal.